FIG. 1 is a view showing the configuration of a packet communication system that provides multicast packet communication services (Multimedia Broadcast/Multicast Services) (hereinafter referred to as “MBMS”). In MBMS, control station apparatus (hereinafter referred to as “RNC”) 10 duplicates MBMS data and transfers the result to base station apparatuses (hereinafter referred to as “Node B”) 11. In FIG. 1, the solid line shows the signal flow in the user plane (hereinafter referred to as “U-plane”), and the dotted line shows the signal flow in the control plane (hereinafter referred to as “C-plane”).
Service center (Broadcast/Multicast Service Center) (hereinafter referred to as “BM-SC”) 12 provides MBMS. Core network (hereinafter referred to as “CN”) 13 is comprised of a GGSN (Gateway GPRS Support Node) and an SGSN (Serving GPRS Support Node), which are not illustrated. GGSN performs the setup (i.e. setup for the bearer plane) for transporting MBMS data to and from the SGSN, in accordance with commands from BM-SC 12. SGSN carries out MBMS control for each user (including MBMS multicast service activation, MBMS session start, MBMS registration, MBMS session stop), and transmits MBMS data to radio access network (hereinafter referred to as “RAN”) 14. RAN 14 is composed of RNC 10, Node B 11, and public network 15. To allow efficient transmission of MBMS data, RNC 10 duplicates MBMS data and transmits the result to each Node B 11. Each Node B 11 transmits the received MBMS data to a radio interface. Public network 15 is used to transmit data between RNC 10 and Node B 11. Terminal apparatus (User Equipment) (hereinafter referred to as “UE”) 16 performs MBMS bearer service control, and receives MBMS data.
Non-Patent Document 1: 3GPP TS 23.246 V.6.2.0 (2004-03) Multimedia Broadcast/Multicast Service (MBMS); Architecture and Functional Description (Release 6)